Method of and apparatus for treating dies



40 There is no Patented Mar. 7, 1939 cpms Harry Blount, Baltimore, Md., assigncr to Western Electric Company,

Incorporated, New

York, N. Y.,' a corporation of New Yo k Application May 20, 1936, Serial No. 80,707

8 Claims. (01. 51217) This invention relates to amethod of and apparatus for treating dies and more particularly to a method of and apparatus for grinding or lapping a wire drawing die comprising two complementaryi members having'opposed arcuately concave drawing faces.

,In the'manufacture of metallic strands for various purposes where special irregular cross sections are required having one transverse di- 10 mension considerably greater than another at right angles thereto, and where such strands are made from circularly cylindrical wire, it is found in some instances to be desirable to convert the circularly cylindrical wire into elliptically or fore rolling or drawinginto the final irregular form. An illustrative example of such procedure may be found in the manufacture of copper wire or tape having a Z-shaped cross section such as is used in the manufacture of certain types of electrical coaxial conductor cable. For use in drawing such fiattenegl wire from! circularly cylindrical stock it has been-found advantageous to-use a two part die comprising two complementary members having opposed circularly arcuateconcave working faces which together have a cross section of the form known in geometry and in architecture as the "vesica piscis. Such dies 3 and their use form no part of the present invention but are the sublect of 'copending application- Serial No. 80,706, filed May 20, 1936 by the present inventor. An object of the present invention is to pro-- 5 vide a method of and apparatus for making and restoring the working or drawing surfaces of the. members of a die in a simple, convenient and accurate manner and by meansof simple,'rugged and reliable apparatus. other name for the figure formed by two intersecting circular arcs each concave toward the other than .vesica piscis". For the present therefor and for use in this specification and the claims appended thereto, the words '45 "v'esica and *vesicate. are defined to. mean the ovally cylindrical wire as a preliminary step berigidly with their circularly arcuate working surfaces coaxial with the aperture. 4

- Other objects and features of the invention will appear from the following detailed description of one embodiment thereof taken in 00111160? tion withthe accompanying drawing in which the same reference numerals are applied to identical parts and in which, 4

Fig. 1 is a view in front elevation of a device for working vesicate die members constructed in accordance with the invention:

- Fig. 2 Ba view thereof in section on the line Fig. 4 is a view on a smaller scale similar to 1 Fig. 1 of amodiiled form} Fig. 5 is a sectional view-on the, line i! of Fig. 4, and c Fig. 6 is an enlarged detached view in pers ective of one of the detachable separating members sh wn in Fig. 5.

The device which is the embodiment of the invention as herein disclosed comprises a body 40 preferably. generally cylindrical and having a coaxial cylindrical dimin shed rear portion 4i adapted to be gripped .to the chuck of a lathe or ance behind work held in the body as hereinafter described for a lapping or grindin tool 43 to be held in a tailstock or the like on the'lathe.

'In the front face of the. body 40 is a pair of complementary recesses 44 and I, a description of one of which and its appurtenances will suiilce for both. The recess 44 has straight, parallel horizontal upper and lower walls connected by semicircularly cylindrical end walls, and-a flat vertical rear wall The left hand semicylindrical end wall is the forward continuation of half of the cylindrical inner surface of a bore ll extending intothe body from the rear wall 45. A cylindrical stop pin 41 is housed in the bore 46 and extends out beyond the wall 5 into the recess It, and is formed at its outer portion with a fiat lateral stop suriace or facet 48, a tapped radial bore 4! extends from the outer surface downw'ardly through the upper wall-of the recess at its centerand houses a correspondingly threaded screw I. A tapped bore Si extends horizontally out from the center of the right hand semicylindrical end wall of the recess through the peripheral surfaceof the body and houses a correspondingly threaded screw 52. In the lower half of the body the elements I toJI! inclusive,

correspond respectively to the elements 44 to 52 inclusive of the upper half.

The two complementary members of a vesicate die to be lapped are shown in position in the device in Figs. 1 and 2. The upper member comprises a substantially rectangularly parallelo-pipedal body 22, preferably of suitably heat treated steel, in which is mounted an insert 24, preferably of tungsten carbide. Ihe conical working faces 34 and 35 and the cylindrical working face36 are formed wholly on the insert while the relief face 31 is formed partly on the insert and partly on the body 22. The two die halves are complementarily identical and in use are placed abutted together with their inserts toward each other so that the aperture between them defined by the circularly arcuate facets 34, 35, 36 and 31 is vesicate in form.

In the device 40 the wall 53 between the recesses 44 and I44 is of such carefully predetermined thickness, that when the die members are locked against the wall 53 and against the stop faces 48 and I48, the circularly arcuate facets 34, 35, 36 and 31 of both inserts 24 and all have their centers in the axis of the bore 42 which is also the axis of the cylindrical periphery of the body portion 4|. Hence when the whole assembly is chucked in a lathe or the like by-means of the portion 4|, the working facets of the inserts will revolve accurately about their own centers, and if a lapping tool such as illustrated in Fig. 3 be held coaxially in and between the inserts 24 and 25, it will have precisely the desired and intended effect of affecting the entire surface of the particular facet matched by its taper on both inserts simultaneously and evenly.

Thus a rough cut pair of new die members may be ground and lapped to size and polish in one operation and with one tool simultaneously as to each facet, thereby ensuring identity of the two halves as to shape. Furthermore this method and apparatus enables the manufacture with simple rotary procedure of a die having a noncircular hole avoiding all the uncertainties and dissymmetry and time consumption consequent upon grinding and polishing with a reciprocating wire or other strand.

When a pair of such vesicate die members is too worn for further use their abutting faces may be cut back by the trifling amount necessary, and

new facets of the same form and dimensions may be cut by the use of the device 40, thus restoring the dies. Or the dies may be recutin the device 40 without cutting back their abutting faces, but witha larger tool 43 for use on a larger size of stock.

A slightly modified form of the device is dis- V closed in Figs. 4, 5 and 6, in which the separating walls 53 between the recesses 44 and I44 and integral with the body 40, of Figs. 1 and 2 are replaced by removable and interchangeable members or blocks 253 attached to and accurately positioned on the body 40 by means of dowels 54 and screws 55. The enlarged inner portions 55 of the members 253 may be made of a width appropriate to the curvature of a given pair. of inserts 24 and 25, and thus by interchange of the members 253 the devicemay be adapted to properly hold paired inserts for grinding of a considerable range of curvature;

It is to be noted that while the disclosure is of a pair of inserts 24, 25 having their arcuate faces of the same radius, the invention is not confined to this condition. So long as the chords of the two arcs are of the same length, their radii may have any .value within this last limitation and the sagittas of the two arcs need not be equal. In any case however the width of the wall 53 or member 253 between the inserts must be equal to the sum of the radii of the two arcs diminished by the sum of the sagittas. If the two inserts have arcs of different radii they will be set in the device and treated one at a time.

The embodiments of the invention herein disclosed are illustrative only and may be widely modified and depa'rted from in many ways without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1. A rotatable cylindrical device for holding members of a non unitary die each having an arcuate working facet thereon, which device comprises a body having two parallel recesses symmetrically disposed therein with respect to its periphery to receive the two members, a wall between the two recesses of such thickness as to space the members with their arcuate facets coaxial with each other, means to clamp the members against the wall, and means to position and clamp the members in alignment with each other.

2. A rotatable cylindrical device for holding members of a non unitary die each having an arcuate working facet thereon, which device comprises a body having two parallel recesses symthereon, which device comprises a body having two parallel recesses therein to receive the two members, a stop in each recess to be abutted by one end of a die member in that recess, a screw mounted in the body to force each die member against its stop, a wall between the two recesses of such thickness as to space the members with their arcuatefacets coaxial with each other, and

a screw mounted in the body to force each die member against the wall.

4. A method of treating a die having a plurality of parts each having an arcuate working facet thereon, which method comprises positioning two parts of the die with their arcuate facets coaxial with each other, and applying a single' grinding means to the plurality of arcuate facets simultaneously.

5. A method of treating a die having a plurality of parts each having an arcuate working facet thereon, which method comprises positioning two parts of the die with their arcuate facets coaxial with each other, and app y ng a single rotary grinding means simultaneously to the several arcuate facets, the parts being so proportioned and arranged that each facet while being ground also serves to support the grinding means to grind another facet.

6. A methodof treating a die having two mutually abutting parts each having an arcuate working facet on that face thereof which abuts against the other part to coact with the facet thereon, which method comprises cutting back working facet on that face thereof which abuts against the other part to coact with the facet thereon, which-method comprises cutting back the mutually abutting faces of the parts, positioning two parts of the die with their arcuate facets'coaxial with each other, and applying a .single rotary grinding means simultaneously to the several 'arcuate facets, the parts being so proportioned and arranged that each facet while being ground also serves to supportthe grinding means to grind another facet.

8. A device for treating members of a nonunitary die each having an arcuate working facet thereon, which device comprises a'body having two parallel recesses therein to receive the two members, a wall between the two recesses of such thickness as to space the-members with their arcuate facets, coaxial with each other; means to clamp the members against the wall, and means to position and clamp the members in alignment with each other, in combination with rotary grinding means dimensioned to enter between the arcuate working facets to grind the same simultaneously, the parts being so proportioned and arranged that each facet while being ground also serves to support the grinding means to grind another facet.

HARRY BLOUNT. 

